HARDWICKE'S SCIENCE-GOSSIP. 



167 



that I am well aware that both the magpie and 

 carrion crow are apt to collect in parties at their 

 several roosting quarters, but I never before heard of 

 their associating in such astonishing numbers. 

 Perhaps I should confine these last observations to 

 England ; for in Northern France the magpie may 

 be seen in unlimited numbers, and in Norway I have 

 found the carrion crow (the hooded variety) to be 

 equally numerous, but both magpie and carrion 

 crow are getting very scarce in this country. — A. C. 

 Smith, Yatcsbury Rectory, Calne. 



Sheet-Lightning. — Kundt, of Zurich, examined 

 spectroscopically more than fifty flashes of lightning 

 and found that forked flashes gave spectra of lines 

 while sheet lightning yielded spectra of bands. The 

 lines indicate a greater degree of heat than the bands, 

 and hence it is concluded that zigzag flashes are 

 electrical discharges between the clouds and the 

 earth, and sheet flashes, merely brush discharges 

 between clouds. The latter are more frequent than 

 the former, the numbers being, according to Kundt, 

 as II : 6. Summer lightning, or, as it is often called, 

 heat lightning, is probably due to the reflection by 

 the clouds above the horizon of discharges which 

 are taking place below it. Many years ago I witnessed 

 an example of this. On a perfectly serene night 

 I noticed the eastern horizon brightly illuminated 

 every few seconds. No thunder was audible. I 

 afterwards ascertained that on the same night a 

 severe thunderstorm was experienced about fifty 

 miles to the north-eastward of the place where I was 

 staying. — J . A. B. Oliver. 



■ Sheet Lightning. — On what grounds does 

 Mr. Stodder believe that sheet and forked lightning 

 are identical manifestations of electrical discharge ? 

 If the cases of sheet-lightning which he has observed 

 can all be explained as he states, the number of his 

 observations must be very limited. How can he 

 account for sheet-lightning accompanying a thunder- 

 storm of small range, while it was subsequently 

 ascertained that the sky surrounding the thunder- 

 clouds was clear for many miles ? When next your 

 correspondents note this effect, if they will make due 

 inquiry, I predict that they will learn that veritable 

 sheet-lightning is totally independent of forked 

 lightning in any direction. I grant that some of 

 the flashes we see may be the reflections of distant 

 sparks, but as they are not due immediately to the 

 discharge they do not constitute veritable sheet 

 lightning. When there are certain conditions, 

 under which sheet lightning occurs, which allow 

 only the explanation that it is a brush discharge, why 

 should we deny the possibility or probability of 

 Nature, with all her magnificent store of energy, 

 producing on a far grander scale a phenomenon 

 which we can easily produce in our laboratories ? 

 The. habit of getting out of difficulties by denying 

 the existence of phenomena which we cannot well 

 explain indicates a cramped mind and one which does 

 not fully realise the complex grandeur of Nature. 

 To such men let Hamlet say, 



"There are more things in heaven and earth, Horatio, 

 Than are dreamt of in our philosophy." 



— Walter G. Woollcomhe. 



Ranunculus acris. — I should be glad if any of 

 the readers of Science-Gossip could give me the 

 distinguishing features oi Ranunculus acris var. tomo- 

 fhyllus, and of the three forms of Brassica rapa, 

 which are given in the seventh edition of the London 

 Catalogue. — J. A. Wheldon. 



Double Flowers.— Whilst botanising in the 

 district of Abram, near Leigh, Lancashire, on the 

 28th of May, I found in a swamp near Plank Lane 

 Collieries, Caltha palustris (marsh marigold) quite 

 double, the flowers resembling trollius, but darker 

 in colour. In the next field I got Cardamine pra- 

 tensis (ladies' smock), double also. Will some 

 readers of Science-Gossip please say if they have 

 met with either of these, double, in the Manchester 

 District before ? — John Slater. 



Pin-eyed double Primrose, etc.— In reply to 

 E. Bally, I found a " pin-eyed " flower of the prim- 

 rose "double" — as described by him — at a wood 

 near here (Cambridge) last year ; this year I found a 

 similar abnormal development in a "thrum-eyed" 

 flower of the same species. I have also found the 

 primrose, oxslip, and cowslip growing together in 

 the same locality, associated with various transitional 

 forms ; on the one hand flowers not differing in size 

 and colour from those of the primrose, but on a 

 stalked umbel, on the other, flowers much smaller 

 than those of the ordinary oxslip. There is also some 

 variation in the size of the corolla in different flowers 

 of the primrose, and a small beetle appeared abun- 

 dant in them. In a corner of our garden the Robert 

 geraniu7)i is growing with white flowers this year ; I 

 also found white Lamium purpurcu/n a little while 

 ago.— C H. Bryan. 



NOTICES TO CORRESPONDENTS. 



To Correspondents and Exchangers. — As we noiv 

 publish Science-Gossip earlier than heretofore, we cannot 

 possibly insert in the following number any communications 

 which reach us later than the 8th of the previous month. 



To Anonymous Querists.— We receive so many quetles 

 which do not bear the writers' names that we are forced to 

 adhere to our rule of not noticing them. 



To Dealers and others. — We are always glad to treat 

 dealers in natural history objects on the same fair and general 

 ground as amateurs, in so far as the " exchanges " offered are fair 

 exchanges. But it is evident that, when their offers are simply 

 disguised advertisements, for the purpose of evading the cost of 

 advertising, an advantage is taken oi owr gratuitous insertion of 

 "exchanges" which cannot be tolerated. 



E. PoORE.— Your plant is the ivy-leaved toad-flax {Linaria 

 cyiiibatariutn). For instructions as to preserving and drying 

 plants, see chapter on that subject in " Notes on Collecting and 

 Preserving Natural History Objects," published by Bogue, 

 3 St. Martin's Place, at 3^-. td. 



E. Halse.— Your article is in hand, and will appear shortly. 

 G. P. Townend.— If Keating's Insect Powder has failed to 



destroy your cockroaches it is difficult to suggest any other 

 remedy. We have heard that foxglove leaves strewn about 

 the rooms infested by these pests will get rid of them. You had 

 best try the experiment. 



G. W. Bkady. — The leaves are not attacked by a fungus, but 

 by a species of Cynips, an insect which produces galls and 

 other excrescences on leaves and buds. 



Doad.— Get the 2S. (yd. vol. published by the Christian 

 Knowledge Society, by the late Professor Ansted, called " In 

 Search of Minerals." Also the cheap work on mineralogy 

 published by Collins Co , Glasgow. Dana's " Manual " is 

 by .far the best book of the kind for a beginner who means 

 earnest study. You will there find what implements, &c., are 

 necessary. 



J. S. A. — Write to the Secretary of the Geological Society of 

 Edinburgh, who will, we have no doubt, give you all the in- 

 formation you seek. 



F. A. Dickens.— The name of the hornet is Vespa crabro. 

 It belongs to the same genus of hymenoptera as the wasps. 



E. PooRE. — You will find articles in the last two or three 

 volumes of Science-Gossip giving details as to how flowers 

 should be pressed, &c., so as to preserve their colours. Par- 

 ticularly look for articles by J. W. Buck. 



E. O. Cox. — The extracted chlorophyll reached us in a high 

 state of decomposition, and it was quite impossible to detect any 

 fungi. 



A. W. Stokes. — Accept our best thanks for your kind offers. 

 We hope to avail ourselves of them. 



